The present applicants have previously discovered that antioxidants which are stable under ambient conditions for extended periods may be obtained by water extraction of plant tissues, and that such antioxidants are absorbed percutaneously, and exert an antioxidant effect on the outer and inner layers of the skin. These effects are advantageously obtained when the antioxidant is applied to the skin as a dispersion in a hydrophilic or hydrophobic base. The observable results of the application of the antioxidant comprise a softening of the skin which is detectable by touching with the fingertips, as well as a reduction in the peroxide level of the skin.
A vast literature exists relating to the treatment of diseases of various kinds, with substances obtained from plants.
Thus, for example, in GB No. 1105769 (Seifert), fully grown plants of the Urticaceae species (e.g. nettles) are fertilized with urine of persons having certain diseases (diabetes, cancer or blood diseases) and are made up into aqueous solutions or tinctures. The resultant homeopathic preparations may be used to treat these diseases, by the internal administration route.
In GB No. 1141573 (Eiji Yamada), there are disclosed substances said to stimulate the function of the reticuloendothelial system, which are obtained by treating unicellular green algae successively with water, alkali and (optionally) acid, removing impurities from each extract by precipitation using lead acetate, and precipitating the desired materials from the respective filtrates by adding alcohol.
In GB No. 1335181 (Cobb), species of plants defined as belonging to the family Compositae tribe Cynareae, subtribe Centaureineae are subjected to fractionation of the juice and/or solvent extraction (e.g. with ethanol or chloroform) of the plant, to give a substance having antineoplastic activity. The plant material may for example be crushed by pressure to extract the juice, and the latter is tested for activity either undiluted or diluted.
In GB No. 1337205 (Yoshizo Sakamoto et al), specified materials of plant origin are subjected to dry vacuum distillation at 40.degree. to 60.degree. C. Both residue and distillate are pharmacologically active.
In EP No. 0030444 (Yasuhiko Kojima et al), a substance having interferon inducing activity is extracted (e.g. with water) from the tissues of plants belonging to specified botanical genuses.
In WO 81/01517 (Kazuyoshi Morita), an active fraction containing mutagenicity-inhibiting material, which is water soluble, is isolated and purified from burdock juice.
None of the foregoing patents relates to the treatment of skin viral diseases by topical administration of an active substance.
In GB No. 1105474 (Sela et al), virus infected plant tissue is macerated with water and infective virus removed from the filtrate; the latter contains a substance of antiviral activity which may be further concentrated by chromatography. The product is stated to apparently contain protein and RNA. Experiments show that it prevents or reduces the level of viral infections in plants. No supportive data is provided to support a suggestion that it may also be used for prevention or treatment of virus infections in livestock and humans. There is no evidence that the material has antioxidant properties or that it can be used to treat viral skin infections in animals or humans by topical application. The data given appears to show merely that an antiviral factor extracted from a plant infected with a particular virus is specific for treatment of the same virus.
In EP No. 0133151 (Berman), there is disclosed an ointment for the treatment of what are termed "skin diseases" (but which on closer inspection appear to be rather intrinsic conditions such as psoriasis, hemerrhoids, varicose veins, acne and eczemas) which comprises an emulsion comprising extracts of a plurality of plants, selenium rich water and a carrier. There is no disclosure of any aqueous extract of plants having antioxidant activity; only extracts in alcohols are mentioned specifically.
In EP No. 0054486 (Cervelle et al), a pharmaceutical composition which may be used for topical treatment of skin virus diseases contains as active ingredient the total extract of Hedysarum Fructescens Willd, consisting essentially of flavanoids, catecholic tannins and phenolic acids, in absence of alkaloids. In practice, the extraction agent is alcohol, aqueous alcohol or propyleneglycol. Although this patent relates to an active ingredient for the topical treatment of skin virus, there is no evidence that the invention thereof can be effected by utilization of extraction with water. It is also self-evident that extraction with water according to the present invention would leave behind water-insoluble materials extracted by the organic solvents, used for the purpose of total extraction, according to Cervelle. Further, this patent contains no disclosure that the extracted ingredients provide an antioxidant effect when applied to the skin, as is required by the present invention.
It has now been surprisingly discovered by the present inventors, and this discovery forms the basis for the present invention, that antioxidant materials extracted from plant tissue with water, and which provide an antioxidant effect when applied to the skin, are useful in treating viral infections of the skin, and conditions of the skin resulting from such viral infections. So far as the applicants are aware, there is no established relationship between antiviral activity and antioxidant activity, such has been unexpectedly found in the present instance. Moreover, the antioxidant materials described herein have been found to be useful for inhibiting at least certain kinds of warts which are known to be due to viruses.
The stable, water soluble plant-extracted antioxidants which have found to be useful in the present invention, are disclosed in U.S. patent application Ser. No. 846,599, filed Mar. 31, 1986, (a continuation-in-part from application Ser. No. 726,540, filed Apr. 24, 1985) as well as in European Patent Application No. 0201956 published Nov. 20, 1986.